This application claims the priority of German Application No. 198 42 630.5, filed Sep. 17, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a mountable centering element and an arrangement for measuring, or determining the position of, a hole or a bolt constructed on a component, particularly of a welded bolt or a threaded bolt, which can be placed on a first side of the component on a component surface surrounding the hole or the bolt.
In numerous technical applications, it is necessary to determine the exact positions or spacings of a number of holes and/or welded or threaded bolts constructed in the component in order to measure the component. For example, in the field of monitoring vehicle body shells as well as their subgroups, such as attached sheet metal parts or individual parts, by measuring techniques, such measurements must be carried out frequently. Because the holes or bolts or their centers, are not directly accessible, it is difficult to make such precise measurements without requiring high expenditures.
In addition, the measurements of holes often have tolerances so that it is expedient to determine the hole centers. The conventional measuring of welded or threaded bolts also have high measuring errors. A large number of individual measurements and reviews must be carried out in order to calculate a corresponding center by way of corresponding perpendicular and sectional calculations. When a measuring caliper is used on threaded screws, a problem occurs in that the measuring caliper, as a rule, does not arrive at the highest point of the thread pitch so that significant errors also occur here.
From German Patent Document DE-PS 936 895, an arrangement is known for measuring distances on an object. The arrangement is introduced into a hole of the object to be measured. The arrangement consists of two separate parts, specifically a shaft which fits into the hole of the object and a part which ends in a ball of a defined radius of curvature. This ball can be positioned such that it is used as a reference point with respect to the center of the hole. In this arrangement, it is a disadvantage that only a pin is introduced into the hole to be measured. The pin cannot be completely fixed inside the hole. This results in measuring errors during measuring.
From German Patent Document DE-PS 733 370, a device is known for measuring spacings of connection points, particularly points, such as ball centers, which cannot be measured directly. This device consists of a main scale with longitudinally adjustable slider bodies and measuring elements which can be displaced in the slider bodies transversely to the main scale. This relatively large device is unsuitable, for example, for measurements at inaccessible sites.
The German Design Patent G 91 06 101 discloses a precision measuring stick which, by inserting a spike into an opening, permits a measuring of the diameter of the opening. The precise determining of the position of the opening is not the object of the teaching described in this document.
It is an object of the present invention to provide an arrangement by which a precise and inexpensive measuring of, or determining the position of, holes or welded or threaded bolts of a component is permitted in a simple manner.
This object is achieved by a mountable element for measuring or determining the position of, a hole or bolt constructed on a component, particularly of a welded bolt or a threaded bolt, which can be placed on a first side of the component on a component surface surrounding the hole or the bolt. The mountable element has an internal thread, which can be screwed together with a fixing screw, which can be introduced into the hole from a second side of the component, for fixing the mountable element on the component while clamping the component between the mountable element and the fixing screw, or with the bolt or a fixing bush adapted to the outside diameter of the bolt.
According to the invention, a mountable element or one or more arrangements are provided by which the precise determination of the position of holes or recesses or welded or threaded bolts, for example, on a body of a motor vehicle, can be carried out in a simple manner. The mountable elements according to the invention can be used in a flexible manner for measuring holes as well as threaded bolts. Measurements at inaccessible sites, for example, the floor panel of a vehicle body, can be carried out without any problem. The mountable element according to the invention is distinguished by lower manufacturing costs as well as fast mountability and demountability. Adaptations to different thread pitches can be carried out in a simple manner by corresponding further developments of the internal-thread of the mountable element.
When an arrangement according to the invention is used for measuring or determining the position of a hole, the mountable element and a fixing screw are mounted on the hole, or inserted in the hole, from opposite sides of the hole and screwed to one another. As a result, a positionally precise clamping fixing of the arrangement or of the mountable element on the component can be achieved.
When an arrangement according to the invention is used for measuring or determining the position of a bolt on a component, a fixing bush, which corresponds to the outside diameter of the bolt, can be screwed into the internal thread of the mountable element. The mounting and demounting takes place by the fitting on and withdrawal of the arrangement from the bolt or bolts to be measured. In this case, it is particularly advantageous to provide a magnetic insert in the mountable element, which ensures a good tight fit around the bolt. The mountable element can have a knurled construction, which permits a particularly simple demounting of the mountable element. As the result of a flexible exchange of the fixing bushes of different diameters, different bolt diameters can be measured by means of a mountable element, whereby the mountable element assumes an adapter-like function. Exchanging the fixing bush can be carried out, for example, by means of a screwdriver. A hardening of the fixing bush was found to be particularly advantageous so that a wearing-off of the fixing bush diameter can be avoided, whereby a high durability is ensured.
Advantageous further developments of the invention are described herein.
According to a preferred embodiment of the mountable element according to the invention, this mountable element has an essentially hemispherical or partially spherical outer contour or shape. The measuring of such hemispherical or partially spherical elements was found to be particularly simple and inexpensive. For example, a bolt to be measured can deviate with respect to its position in all directions up to 5 mm from its desired position without an interruption of a CNC series measuring sequence during the measuring of the ball-like mountable element by means of collision. The process steps in the ball measuring CNC sequence are always the same. The ball element can always be mirrored during the programming if the positions of the bolts with respect to one another in the slope do not significantly deviate from one another. Particularly, during the measuring of such ball shapes, the good tight fit of the mountable element is advantageous. The roundness of the mountable element and the precise centering of the internal thread determine in a very exact manner the center of a bolt to be measured and thus provides the actual condition of the bolt on the pertaining component surface. It should be noted that the mountable element according to the invention may also have a cornered construction, particularly that of a hexagon or an octagon. Preferred materials for the mountable element are plastic materials, metals or other suitable materials. By using magnetic materials, for example, an adhesion of the mountable element on a component can also be ensured prior to being screwed to a bolt or a screw. Hemispherical shapes with diameters of from 15-35 mm can be used particularly advantageously in practice.
The mountable element expediently has a supporting ring on its underside. This ensures that the mountable element can lie closely on the component also in the presence of an uneven component surface in the proximity of the hole or bolt (for example, caused by welding spatters, burrs from punching or bolt bases). Such a supporting ring may, for example, have a ring thickness of 2 mm in the case of an inside ring diameter of 17 mm.
According to a preferred embodiment, the mountable element has a bevel on its lower edge. Such a bevel, which preferably has an angle of approximately 45xc2x0, ensures an injury-free screwing-on and unscrewing as well as a good handling of the mountable element according to the invention by a user.
According to another expedient embodiment, the internal thread is asymmetrically arranged with respect to the mountable element. By means of this measure, it is possible to measure holes or bolts at inaccessible edge areas or in the run-out of roundings of a component. In the case of a hemispherical or partially spherical outer contour of the mountable element, such an asymmetrical construction can be achieved, for example, by means of a one-sided or two-sided milling-off of the mountable element.
According to an advantageous embodiment of the mountable element according to the invention, the internal thread is constructed as a through-thread. As a result, it is possible to measure bolts or screws of any length by using the mountable element according to the invention.
The mountable element expediently has an insert, particularly a ring-shaped insert, made of a magnetic material. Particularly when the mountable element is used together with a fixing bush which can be slid onto a bolt, such an insert ensures a good tight fit on the bolt, whereby high measuring precision can be achieved.
According to a preferred embodiment of the arrangement for measuring, or determining the position of, a hole, the fixing screw has a conically tapering section. By means of such a conical section, a particularly secure and positionally precise fixing of the fixing screw can be achieved in a hole.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.